Researchers find link between ‘killer cells’ and immunity

Brown and McGill University researchers have discovered an important relationship between cells of the immune system — a finding that might someday benefit patients receiving bone marrow and organ transplants.

T-cells — named for the thymus, where they mature — attack pathogens in the body but can sometimes harm healthy tissue. Natural killer cells, or NK-cells, were previously known to respond to viral illnesses by destroying infected cells, but have now been found to also play a key role in regulating T-cells by secreting a protein that controls inflammation.

Because NK cells prevent the immune system from over-activating, controlling the cells’ growth could help prevent organ rejection.

Professor of Medical Science Christine Biron, who has been working with NK cells for more than two decades and was senior author of a paper on the discovery, said the finding, published in last month’s Journal of Experimental Medicine, was somewhat unexpected.

“The relationship hinted at in the paper is surprising and novel,” Biron said. “It helps explain a lot of observations that were difficult to explain in the past.”

Still, there is much to be done before the finding affects patient care, said Biron and Seung-Hwan Lee, a postdoctoral research associate and first author of the team’s published paper.

“To tell you the truth, we are doing very basic immunology,” Lee said. “To see a translation might take some time.”

Before medical procedures can incorporate the new research, Biron said, host-pathogen relationships and the delicate balances within the immune system must be understood better.

“The challenge of the immune system is that it is very well-armed and can do a lot of good, but it has to be regulated,” Biron said. “It’s more like Goldilocks and the three bears: There’s too much and there’s too little, and there’s just right. You have to optimize responses.” Lee voiced a similar view regarding immune cell dynamics: “The body knows what is best. As long as we maintain NK-cells and T-cells, they will know what to do.”

Biron and her research team hope to build on their current understanding of NK-cell function. Though basic NK-cell biology has been established, there is still uncertainty regarding the behavior and activation of cell receptors and signaling pathways in the immune system, Biron said.

With a better understanding of the intricacies of immune responses, Lee said he anticipates finding more mechanisms beneficial to host organisms.